126 UP THE OrjNOCO. 



if he supply his stomach, from time to time, Avith earthy 

 insipid substances, that are not in themselves fit for nutri- 

 tion." * This habit of eating dirt is prevalent among the 

 Indians of Brazil, and vre learned from foreign residents 

 upon the Marauon that their children evinced a morbid 

 appetite for earths, that they sought gratification in swal- 

 lowing large lumps of innutritions clay. 



Departing from this Indian encampment, we poled to 

 the upper end of the playa, Avhich was a league in length, 

 and one-third that in width, and there encamped. The 

 heat of the sun was most intense, and the plain was undu- 

 lating, like the surface of disturbed water, from the eftects 

 of mirage, and every object about us appeared to be ele- 

 A'ated and dancing in the air. This singular atmospheric 

 phenomenon, occasioned by the refraction and reflection 

 of light in traversing the strata of rarefied air next the sur- 

 face of the earth, is common upon the arid j^layas of the 

 Orinoco. AYe sometimes saw the long line of barren coast 

 apparently in greater agitation than the river upon which 

 we were sailing ; but, approaching, instead of floating into 

 rougher water, we would land upon a sandy, burning 

 shore. 



We roamed the playa in search of turtles' eggs, but 

 found only a few, which were those of the terecai ; it unfor- 

 tunately not being the season for the great harvest of eggs, 

 which occurs in the months of April and May. From the 

 natives, however, we gathered many interesting facts re- 

 specting the " egg -harvest," and by them were made 

 acquainted with the habits of this reptile, which is found 

 in such prodigious numbers upon the Orinoco, between 

 the cataracts and the mouth of the Apure. To Paez, and 

 other traA'ellers on the Orinoco, we are also indebted for 

 much valuable information concerning this animal. The 

 great turtle, called by the Spaniards tortuga, and by the 

 * " Humboldt's Travels," vol. ii., p. 502. 



